using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Text;

public class MarksMoveViewStateMod : IHttpModule
{  

    void IHttpModule.Init(HttpApplication context)
    {
        // Add Event
        context.BeginRequest += new EventHandler(context_BeginRequest);
    }

    void context_BeginRequest(object sender, EventArgs e)
    {
        HttpApplication _HttpApp = sender as HttpApplication;
        if (_HttpApp.Request.Url.OriginalString.Contains(".aspx"))
        {
            _HttpApp.Response.Filter = new ViewstateFilter(_HttpApp.Response.Filter);
        }
    }

    private class ViewstateFilter : Stream
    {
        public ViewstateFilter(Stream TempStream)
        {
            _TmpStream = TempStream;
        }

        public override bool CanRead { get { return true; } }

        public override bool CanSeek { get { return true; } }

        public override bool CanWrite { get { return true; } }

        public override void Flush() { _TmpStream.Flush(); }

        public override long Length { get { return 0; } }

        public override long Position
        {
            get { return _position; }
            set { _position = value; }
        }
        public override int Read(byte[] buffer, int offset, int count) { return _TmpStream.Read(buffer, offset, count); }
        public override long Seek(long offset, SeekOrigin origin) { return _TmpStream.Seek(offset, origin); }
        public override void SetLength(long value) { _TmpStream.SetLength(value); }
        public override void Close() { _TmpStream.Close(); }
        private StringBuilder _DataBuffer = new StringBuilder();
        private Stream _TmpStream;
        private long _position;

        public override void Write(byte[] buffer, int offset, int count)
        {

            string html_part = System.Text.Encoding.Default.GetString(buffer);

            _DataBuffer.Append(html_part);

            // I bet this causes problems with something...  but No definitive way to test for this unless EOF is sent
            // No time to test....
            if (html_part.Contains("</html>"))
            {
                string html = _DataBuffer.ToString();
                html = html.Replace("~/", Utility.BASEURL);
                int startPoint = html.IndexOf("<input type=\"hidden\" name=\"__VIEWSTATE\"");
                // Can Add Other ASP.NEt *** here also
                if (startPoint >= 0)
                {
                    int endPoint = html.IndexOf("/>", startPoint) + 2;
                    string viewstateInput = html.Substring(startPoint, endPoint - startPoint);
                    html = html.Remove(startPoint, endPoint - startPoint);
                    int formEndStart = html.IndexOf("</form>") - 1;
                    if (formEndStart >= 0) { html = html.Insert(formEndStart, viewstateInput); }
                }
                byte[] outdata = System.Text.Encoding.Default.GetBytes(html);
                _TmpStream.Write(outdata, 0, outdata.GetLength(0));
            }
        }
    }    

    void IHttpModule.Dispose()
    {
      
    }

}